diff options
| -rw-r--r-- | Makefile | 37 | ||||
| -rw-r--r-- | arch/Kconfig | 8 | ||||
| -rw-r--r-- | kernel/configs/tiny.config | 4 |
3 files changed, 45 insertions, 4 deletions
@@ -680,6 +680,10 @@ endif # This selects the stack protector compiler flag. Testing it is delayed # until after .config has been reprocessed, in the prepare-compiler-check # target. +ifdef CONFIG_CC_STACKPROTECTOR_AUTO + stackp-flag := $(call cc-option,-fstack-protector-strong,$(call cc-option,-fstack-protector)) + stackp-name := AUTO +else ifdef CONFIG_CC_STACKPROTECTOR_REGULAR stackp-flag := -fstack-protector stackp-name := REGULAR @@ -688,12 +692,18 @@ ifdef CONFIG_CC_STACKPROTECTOR_STRONG stackp-flag := -fstack-protector-strong stackp-name := STRONG else + # If either there is no stack protector for this architecture or + # CONFIG_CC_STACKPROTECTOR_NONE is selected, we're done, and $(stackp-name) + # is empty, skipping all remaining stack protector tests. + # # Force off for distro compilers that enable stack protector by default. - stackp-flag := $(call cc-option, -fno-stack-protector) + KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector) +endif endif endif # Find arch-specific stack protector compiler sanity-checking script. ifdef stackp-name +ifneq ($(stackp-flag),) stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh stackp-check := $(wildcard $(stackp-path)) # If the wildcard test matches a test script, run it to check functionality. @@ -705,9 +715,17 @@ ifdef stackp-name ifndef stackp-broken # If the stack protector is functional, enable code that depends on it. KBUILD_CPPFLAGS += -DCONFIG_CC_STACKPROTECTOR + # Either we've already detected the flag (for AUTO) or we'll fail the + # build in the prepare-compiler-check rule (for specific flag). + KBUILD_CFLAGS += $(stackp-flag) + else + # We have to make sure stack protector is unconditionally disabled if + # the compiler is broken (in case we're going to continue the build in + # AUTO mode). + KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector) endif endif -KBUILD_CFLAGS += $(stackp-flag) +endif ifeq ($(cc-name),clang) KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,) @@ -1102,15 +1120,28 @@ PHONY += prepare-compiler-check prepare-compiler-check: FORCE # Make sure compiler supports requested stack protector flag. ifdef stackp-name + # Warn about CONFIG_CC_STACKPROTECTOR_AUTO having found no option. + ifeq ($(stackp-flag),) + @echo CONFIG_CC_STACKPROTECTOR_$(stackp-name): \ + Compiler does not support any known stack-protector >&2 + else + # Fail if specifically requested stack protector is missing. ifeq ($(call cc-option, $(stackp-flag)),) @echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \ $(stackp-flag) not supported by compiler >&2 && exit 1 endif + endif endif -# Make sure compiler does not have buggy stack-protector support. +# Make sure compiler does not have buggy stack-protector support. If a +# specific stack-protector was requested, fail the build, otherwise warn. ifdef stackp-broken + ifeq ($(stackp-name),AUTO) + @echo CONFIG_CC_STACKPROTECTOR_$(stackp-name): \ + $(stackp-flag) available but compiler is broken: disabling >&2 + else @echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \ $(stackp-flag) available but compiler is broken >&2 && exit 1 + endif endif @: diff --git a/arch/Kconfig b/arch/Kconfig index 9330a9d79dc3..76c0b54443b1 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -541,7 +541,7 @@ config HAVE_CC_STACKPROTECTOR choice prompt "Stack Protector buffer overflow detection" depends on HAVE_CC_STACKPROTECTOR - default CC_STACKPROTECTOR_NONE + default CC_STACKPROTECTOR_AUTO help This option turns on the "stack-protector" GCC feature. This feature puts, at the beginning of functions, a canary value on @@ -588,6 +588,12 @@ config CC_STACKPROTECTOR_STRONG about 20% of all kernel functions, which increases the kernel code size by about 2%. +config CC_STACKPROTECTOR_AUTO + bool "Automatic" + help + If the compiler supports it, the best available stack-protector + option will be chosen. + endchoice config THIN_ARCHIVES diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config index 7fa0c4ae6394..9bfdffc100da 100644 --- a/kernel/configs/tiny.config +++ b/kernel/configs/tiny.config @@ -10,3 +10,7 @@ CONFIG_OPTIMIZE_INLINING=y # CONFIG_SLAB is not set # CONFIG_SLUB is not set CONFIG_SLOB=y +CONFIG_CC_STACKPROTECTOR_NONE=y +# CONFIG_CC_STACKPROTECTOR_REGULAR is not set +# CONFIG_CC_STACKPROTECTOR_STRONG is not set +# CONFIG_CC_STACKPROTECTOR_AUTO is not set |